1. Field of the Invention
The present invention relates to an imaging element, an image reading device, an image forming apparatus, and an imaging method.
2. Description of the Related Art
In complementary metal-oxide semiconductor (CMOS) image sensors, there has been known the one that performs analog signal processing and digital signal processing in a chip so as to receive light, convert the received light to an analog signal, and further convert the analog signal to a digital signal. In this case, noise generated in a digital circuit may be superimposed on an analog signal, thereby degrading an image signal.
Japanese Patent No. 4481758 discloses a signal processor that outputs a signal stored in a line memory in a period other than a noise canceling period in a horizontal scanning period through an output circuit and control the line memory so that logic noise in a digital signal processing circuit and output noise at an output terminal are not generated in the one horizontal noise canceling period.
In the conventional technique, outputting a signal in a period other than a noise canceling period through an output circuit reduces mixture of noise into the signal; however, the signal cannot be prevented from being degraded due to noise generated at other timings.